1. Field of the Invention
The present invention relates to a conveyor system for conveying a workpiece while supporting a lower surface of the workpiece during processing, and more particularly to a conveyor system including a plurality of support members which are erected upwards and spaced apart from each other.
2. Related Art
When cutting, heat treating or surface treating a workpiece by laser beam, water jet, plasma arc discharge or gas burner, in the event that the workpiece is directly placed on a table, there may be a problem that a surface of the table is damaged by the laser beam which has passed through the workpiece. In addition, there may be a problem that a portion of the workpiece which should not be processed or a laser beam emitting apparatus is damaged by the laser beam which has passed through the workpiece and reflected on the surface of the table. Additionally, there occurs a situation in which an assist gas cannot be discharged with good efficiency and the processing of the workpiece cannot be performed well.
As a countermeasure against these problems, there is known a table in which a plurality of support members are erected upwards while being spaced apart from each other and workpiece is supported by distal ends of the support members. In the table, a risk that a laser beam passes through the workpiece and is irradiated on to the table is extremely reduced, whereby a risk of damaging the table is reduced correspondingly. However, when a working position and a supporting position coincide to each other, the laser beam that has passed through the workpiece is still irradiated on to the distal end portions of the support members to thereby damage the support members. In addition, the workpiece cannot be processed well, and the problems cannot be solved completely.
Then, there is reported a configuration in which a plurality of pins are disposed into a matrix on a pedestal and the support pins which are disposed below a cutting position of a workpiece are selectively raised and lowered (refer to JP-U-62-077688, for example). The support pins are provided on a belt conveyor so as to be raised and lowered by selectively energizing electromagnets.
In the conventional pedestal, however, since the support pins are provided on the belt conveyor so as to be raised and lowered by selectively energizing the electromagnets, the raising and lowering of the support pins has to be carried out by moving the belt conveyor at a very slow speed or temporarily stopping the belt conveyor, thereby making it difficult to carry out the continuous processing or cutting of the workpiece. In addition, in the pedestal, the support pins can be moved only in the vertical direction, and therefore, a degree of freedom in disposition of the support pins is largely limited.